将Log4j模式布局扩展转换为Log4j2

Question

我正在将一个大型应用程序从Log4j1转换为Log4j2，并找到了这个类。PatternLayout不能在Log4j2中扩展，但我知道我使用插件将这个类转换为Lug4j2。我查看了这些教程(扩展Log4j2，Log4j2Plugins，用Log4j2ProgrammaticConfiguration(，但我仍然不确定如何准确地做到这一点。在我看来，我只能应用教程，如果它是所呈现的确切用例的话。有人能帮我吗？如何获取具体信息？我必须查看Log4j2源代码吗？

package aa.bbb.cccc;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import org.apache.log4j.Level;
import org.apache.log4j.spi.LocationInfo;
import org.apache.log4j.spi.LoggingEvent;
public class PatternLayout extends org.apache.log4j.PatternLayout {
private static final SimpleDateFormat DATE_FORMAT;
/**
* ANSI-Format for the level
*/
private static final HashMap<Level, CliColor> LEVELS;
static {
LEVELS = new HashMap<Level, CliColor>();
LEVELS.put(Level.TRACE, CliColor.BLUE);
LEVELS.put(Level.DEBUG, CliColor.CYAN);
LEVELS.put(Level.INFO, CliColor.GREEN);
LEVELS.put(Level.WARN, CliColor.YELLOW);
LEVELS.put(Level.ERROR, CliColor.RED);
LEVELS.put(Level.FATAL, CliColor.RED);
DATE_FORMAT = new SimpleDateFormat("HH:mm:ss,SSS");
}

/**
* Pads a string until it has the desired length. The space
* is filled with spaces.
*
* @param str The string to pad.
* @param length The desired length of the string.
* @return A padded string.
*/
public static String leftPad(String str, int length) {
if (str.length() > length) {
return str.substring(0, length);
}
if (str.length() < length) {
StringBuilder stringBuilder = new StringBuilder(str);
for (int i = str.length(); i < length; ++i) {
stringBuilder.append(' ');
}
return stringBuilder.toString();
}
return str;
}
@Override
public String format(LoggingEvent event) {
return String.format("%s %s %s %sn", DATE_FORMAT.format(new Date()),
formatLevel(event), formatLocationInfo(event),
formatMessage(event));
}
/**
* @param event The event that gets formatted
* @return A string representing the log level.
*/
private String formatLevel(LoggingEvent event) {
Level level = event.getLevel();
String levelName = leftPad(level.toString(), 5);
CliColor ansiConfig = LEVELS.get(level);
if (ansiConfig == null) {
return CliColor.color(levelName, CliColor.BOLD);
}
return CliColor.color(levelName, CliColor.BOLD, ansiConfig);
}
/**
* @param event The event that gets formatted
* @return A formatted location info.
*/
private String formatLocationInfo(LoggingEvent event) {
LocationInfo locationInfo = event.getLocationInformation();
final String line = locationInfo.getLineNumber();
String className = locationInfo.getClassName();
className = className.substring(className.lastIndexOf('.') + 1);
return "[u001b[0;33m" + className + ":" + line + "u001B[m]";
}
/**
* @param event The event that gets formatted
* @return Formatted message.
*/
private String formatMessage(LoggingEvent event) {
if (event.getMessage() == null) {
return "";
}
return event.getMessage().toString();
}
}

Answer 1

由于PatternLayout本身就是final，因此您可以扩展PatternLayouts的父类并完成任务。

package com.example;

import java.nio.charset.Charset;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.layout.AbstractStringLayout;
public class HelloPattern extends AbstractStringLayout {
private static final SimpleDateFormat DATE_FORMAT;
/**
* ANSI-Format for the level
*/
private static final HashMap<Level, CliColor> LEVELS;
static {
LEVELS = new HashMap<Level, CliColor>();
LEVELS.put(Level.TRACE, CliColor.BLUE);
LEVELS.put(Level.DEBUG, CliColor.CYAN);
LEVELS.put(Level.INFO, CliColor.GREEN);
LEVELS.put(Level.WARN, CliColor.YELLOW);
LEVELS.put(Level.ERROR, CliColor.RED);
LEVELS.put(Level.FATAL, CliColor.RED);
DATE_FORMAT = new SimpleDateFormat("HH:mm:ss,SSS");
}
protected HelloPattern(Charset charset) {
super(charset);
}
protected HelloPattern(Charset aCharset, byte[] header, byte[] footer) {
super(aCharset, header, footer);
}
protected HelloPattern(Configuration config,
Charset aCharset,
Serializer headerSerializer,
Serializer footerSerializer) {
super(config, aCharset, headerSerializer, footerSerializer);
}
/**
* Pads a string until it has the desired length. The space is filled with spaces.
*
* @param str    The string to pad.
* @param length The desired length of the string.
* @return A padded string.
*/
public static String leftPad(String str, int length) {
if (str.length() > length) {
return str.substring(0, length);
}
if (str.length() < length) {
StringBuilder stringBuilder = new StringBuilder(str);
for (int i = str.length(); i < length; ++i) {
stringBuilder.append(' ');
}
return stringBuilder.toString();
}
return str;
}
@Override
public boolean requiresLocation() {
return true;
}
@Override
public String toSerializable(LogEvent event) {
return String.format("%s %s %s %sn", DATE_FORMAT.format(new Date()),
formatLevel(event), formatLocationInfo(event),
formatMessage(event));
}
/**
* @param event The event that gets formatted
* @return A string representing the log level.
*/
private String formatLevel(LogEvent event) {
Level level = event.getLevel();
String levelName = leftPad(level.toString(), 5);
CliColor ansiConfig = LEVELS.get(level);
if (ansiConfig == null) {
return CliColor.color(levelName, CliColor.BOLD);
}
return CliColor.color(levelName, CliColor.BOLD, ansiConfig);
}
/**
* @param event The event that gets formatted
* @return A formatted location info.
*/
private String formatLocationInfo(LogEvent event) {
Throwable thrown = event.getThrown();
final int line = thrown.getStackTrace()[0].getLineNumber();
String className = thrown.getStackTrace()[0].getClassName();
className = className.substring(className.lastIndexOf('.') + 1);
return "[u001b[0;33m" + className + ":" + line + "u001B[m]";
}
//Tried best to get it right
/**
* @param event The event that gets formatted
* @return Formatted message.
*/
private String formatMessage(LogEvent event) {
if (event.getMessage() == null) {
return "";
}
return event.getMessage().toString();
}
enum CliColor {
BLUE, CYAN, GREEN, YELLOW, RED, BOLD;
public static String color(String level, CliColor color) {
return "stringBasedonyourimplementation";
}
public static String color(String levelName, CliColor bold, CliColor ansiConfig) {
return "stringBasedonyourimplementation";
}
}
}

注意：由于我没有足够的关于CliColor的信息，所以添加了mock impl来告诉你这方面的想法。此外还有位置信息。